The present invention relates to a method for attaching a flexible structure to a device. The present invention further relates to a method for producing an electro-optical device being connectable by means of a flexible structure. Furthermore, the present invention relates to a method for producing a flexible connector. Furthermore, the present invention relates to an electro-optical device and to a flexible connector.
Flexible interconnection elements such as flexible cables (flexible cables) are widely used primarily in order to establish electrical connections. They comprise a stack of flexible polymer-based materials, e.g. polyimide, and embedded metal structures to provide the electrical connection (electrical flexible). Flexible cables may also be used for optical connections (optical flexible) and/or for a flexible mechanical connection (mechanical flexible).
The realization of electrical, electro-optical or microelectro-mechanical (MEMS) type of components is based on integrated circuit (IC) compatible wafer level processes such as silicon technology. Such processes are well developed and standardized and serve as a cost-effective means for fabricating small, micro- and nano-devices. The introduction of flexible structures which provide an interconnection with the devices is required for several applications.
In order to provide a flexible interconnection element connected to a device, such as a bare chip, it is attached to a device which usually has been fabricated by means of applying wafer level processes on a substrate. The techniques for fabricating such a device are based on a bottom-up process flow where layers are subsequently deposited and patterned. The wafer surface is required to be flat or at least existing corrugations should be small with respect to the feature size that has to be realized in the next processing step.
To realize a flexible interconnection element on such a device, further wafer level process steps are required. These further process steps may require a plane surface, the utilization of chemicals and/or the appliance of temperatures which do not affect the structures of the device fabricated prior thereto. In other words, the process steps for fabricating the flexible interconnection element may have to be compatible to the surface unevenness and to the preceding wafer-level-processes for fabricating the integrated device. Furthermore, by applying the flexible interconnection element to an integrated device by means of wafer level processes on the substrate of the integrated device, it is difficult to partly release the flexible interconnection structure from the device surface by means of a wafer-level process which is necessary to provide a flexible interconnection between the device and an external environment.